If I understand it correctly the
Johnson Metysis controllers use basically the simpler Arcnet protocol
In order to communicate with a true Bacnet device or
a Lontalk device, or
a Modbus device
you still need a gateway device connected on the N2 bus
Opennprotocol really does not exist
If you are using a Modbus device on the N2 bus
Can that device share global points with the Johnson controllers
Not much of a Johnson guy but I just did a Bacnet project where I brought over 454 points of info from a N-30 bus.
Pretty easy to accomplish and now I have full control of this building, setpoints and scheduling.
There N-30 was on the LAN and the building is remote of the original job, all I needed was the N-30 Device ID and then scanned for it and bingo.
What kind of gateway did you use